| Parameter |
Value |
| Designation |
C/2005 L2 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2005-07-14T12:31:58.244160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:50Z |
| Obs used |
54 |
| NEO |
- |
| M1 |
14.400 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2005-09-03.0000000 |
| e |
0.99997944 |
| q (au) |
3.193792 |
| a (au) |
155353.269479 |
| i (deg) |
152.764081 |
| Ω (om, deg) |
155.872566 |
| ω (w, deg) |
294.238895 |
| M (ma, deg) |
0.000001 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.144 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.144 |
| n |
2.000 |
| gf |
0.987 |
| gb |
-0.846 |
| k |
0.982 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
04:48:27.45 |
+49:39:52.1 |
HIP 22433 |
12.75 |
| 2026-09-20 12:00 |
04:48:26.02 |
+49:40:10.4 |
HIP 22433 |
13.07 |
| 2026-09-21 00:00 |
04:48:24.55 |
+49:40:28.6 |
HIP 22433 |
13.41 |
| 2026-09-21 12:00 |
04:48:23.04 |
+49:40:46.7 |
HIP 22433 |
13.75 |
| 2026-09-22 00:00 |
04:48:21.49 |
+49:41:04.7 |
HIP 22433 |
14.10 |
| 2026-09-22 12:00 |
04:48:19.90 |
+49:41:22.6 |
HIP 22433 |
14.46 |
| 2026-09-23 00:00 |
04:48:18.28 |
+49:41:40.5 |
HIP 22433 |
14.82 |
| 2026-09-23 12:00 |
04:48:16.62 |
+49:41:58.3 |
HIP 22433 |
15.19 |
| 2026-09-24 00:00 |
04:48:14.92 |
+49:42:15.9 |
HIP 22433 |
15.57 |
| 2026-09-24 12:00 |
04:48:13.18 |
+49:42:33.5 |
HIP 22433 |
15.95 |
| 2026-09-25 00:00 |
04:48:11.40 |
+49:42:51.0 |
HIP 22433 |
16.34 |
| 2026-09-25 12:00 |
04:48:09.59 |
+49:43:08.5 |
HIP 22433 |
16.73 |
| 2026-09-26 00:00 |
04:48:07.74 |
+49:43:25.8 |
HIP 22433 |
17.13 |
| 2026-09-26 12:00 |
04:48:05.85 |
+49:43:43.0 |
HIP 22433 |
17.54 |
| 2026-09-27 00:00 |
04:48:03.93 |
+49:44:00.1 |
HIP 22433 |
17.95 |
| 2026-09-27 12:00 |
04:48:01.96 |
+49:44:17.2 |
HIP 22433 |
18.36 |
| 2026-09-28 00:00 |
04:47:59.96 |
+49:44:34.1 |
HIP 22433 |
18.78 |
| 2026-09-28 12:00 |
04:47:57.93 |
+49:44:51.0 |
HIP 22433 |
19.21 |
| 2026-09-29 00:00 |
04:47:55.85 |
+49:45:07.7 |
HIP 22433 |
19.64 |
| 2026-09-29 12:00 |
04:47:53.74 |
+49:45:24.4 |
HIP 22174 |
19.56 |
| 2026-09-30 00:00 |
04:47:51.59 |
+49:45:40.9 |
HIP 22174 |
19.11 |
| 2026-09-30 12:00 |
04:47:49.41 |
+49:45:57.3 |
HIP 22174 |
18.67 |
| 2026-10-01 00:00 |
04:47:47.18 |
+49:46:13.7 |
HIP 22174 |
18.22 |
| 2026-10-01 12:00 |
04:47:44.92 |
+49:46:29.9 |
HIP 22174 |
17.76 |
| 2026-10-02 00:00 |
04:47:42.63 |
+49:46:46.0 |
HIP 22174 |
17.31 |
| 2026-10-02 12:00 |
04:47:40.30 |
+49:47:02.0 |
HIP 22174 |
16.85 |
| 2026-10-03 00:00 |
04:47:37.93 |
+49:47:17.9 |
HIP 22174 |
16.38 |
| 2026-10-03 12:00 |
04:47:35.52 |
+49:47:33.7 |
HIP 22174 |
15.91 |
| 2026-10-04 00:00 |
04:47:33.08 |
+49:47:49.3 |
HIP 22174 |
15.44 |
| 2026-10-04 12:00 |
04:47:30.60 |
+49:48:04.9 |
HIP 22174 |
14.96 |
| 2026-10-05 00:00 |
04:47:28.09 |
+49:48:20.3 |
HIP 22174 |
14.48 |
| 2026-10-05 12:00 |
04:47:25.54 |
+49:48:35.6 |
HIP 22174 |
14.00 |
| 2026-10-06 00:00 |
04:47:22.96 |
+49:48:50.8 |
HIP 22174 |
13.52 |
| 2026-10-06 12:00 |
04:47:20.33 |
+49:49:05.8 |
HIP 22174 |
13.03 |
| 2026-10-07 00:00 |
04:47:17.68 |
+49:49:20.8 |
HIP 22174 |
12.54 |
| 2026-10-07 12:00 |
04:47:14.99 |
+49:49:35.6 |
HIP 22174 |
12.04 |
| 2026-10-08 00:00 |
04:47:12.26 |
+49:49:50.3 |
HIP 22174 |
11.54 |
| 2026-10-08 12:00 |
04:47:09.50 |
+49:50:04.8 |
HIP 22174 |
11.04 |
| 2026-10-09 00:00 |
04:47:06.70 |
+49:50:19.3 |
HIP 22174 |
10.54 |
| 2026-10-09 12:00 |
04:47:03.87 |
+49:50:33.5 |
HIP 22174 |
10.03 |
| 2026-10-10 00:00 |
04:47:01.00 |
+49:50:47.7 |
HIP 22174 |
9.53 |
| 2026-10-10 12:00 |
04:46:58.10 |
+49:51:01.7 |
HIP 22174 |
9.02 |
| 2026-10-11 00:00 |
04:46:55.16 |
+49:51:15.6 |
HIP 22174 |
8.51 |